Exchange 2007 MRM Rules not working

I'm having an issue with getting an Exchange MRM routine to work. What I am trying to achieve is the transfer of all inbox items over 14 days old in one single mailbox (called corporatespam) to be moved to a custom folder within that mailbox (called cleardown). Once a message has been in cleardown for a further 7 days I want to permanently delete it.

iv) Created a Policy called 'corporatespam cleandown' and added 'inbox' and 'cleardown' folders to this policy

v) Assigned this policy to user 'corporatespam'

vi) Set up a custom schedule for MRM on the mailbox settings to run twice a day

vii) Ran the exchange powershell command 'start-managedfolderassistant -mailbox corporatespam' (in order to not have to wait for the schedule to test.)

viii) Checked event log and made sure I saw events 9021 and 9022 in the event log (MRM has started and MRM has succesfully completed.

ix) Logged on using OWA as user corporatespam. The custom folder 'cleardown' has been created under the folder 'managed folders' as expected. The messages (all 10,000 of them) are still stuck in the inbox though, and go back to August 2008

So it seems that MRM itself is working as the custom folder is created in the mailbox that I applied the policy to. The actual Managed Content Settings themselves don't seem to work. I have also tried creating them to delete directly from the inbox rather than move them to the custom folder first - no joy. I just can't seem to get any of the content settings to work; it's as though I'm missing something obvious somewhere.

Exchange organizations may use the Journaling Agent of the Transport Service to archive messages going through Exchange. However, if the Transport Service is integrated with some email content management application (such as an anti-spam), the admin…